1. Field of the Invention
The present invention relates to an ink jet printer, and more specifically, to a method for printing color images with the ink jet printer.
2. Description of the Prior Art
Please refer to FIG. 1. FIG. 1 is a schematic diagram showing a related art color printhead 450. The printhead 450 includes three central ink flow channels 462 formed on a substrate 461. A plurality of nozzles 464 are arranged in six columns, with each of the six columns of nozzles 464 being located on a side of one of the three central ink flow channels 462. Each of the three central ink flow channels 462 is connected with an associated ink reservoir for providing ink of up to three different colors such as dark cyan, dark magenta, and yellow.
When the printhead 450 prints color images onto a printing medium, the nozzles 464 eject drops of ink during successive passes of the printhead 450 over the medium. For example, a first pass would be when the printhead 450 moves from left to right across the medium. A second pass would be when the printhead 450 moves back from right to left. Unfortunately, the color printhead 450 shown in FIG. 1 can only eject three colors of ink. For example, if a dark cyan dot were to be printed on the medium, the printhead 450 would only need one pass over the medium to eject dark cyan ink on the correct position. In addition, if one of the nozzles 464 of the related art printhead 450 were defective or stopped working, the printhead 450 would need additional passes over the medium in order for other nozzles 464 to compensate for the defective nozzle 464.
It is therefore a primary objective of the claimed invention to provide a method for printing a color image with an ink jet printer in order to solve the above-mentioned problems.
According to the claimed invention, a method for printing a color image with an ink jet printer is disclosed. The ink jet printer includes a printhead having printing nozzles arranged in first, second, and third columns extending in a first direction. Nozzles in the first column are supplied with light magenta ink. Nozzles in the second column are divided into first, second, and third sections. Nozzles of the first section are supplied with dark magenta ink, nozzles of the second section are supplied with dark cyan ink, and nozzles of the third section are supplied with yellow ink. Nozzles in the third column are supplied with light cyan ink. The first, second, and third columns each have a length approximately equal to 3*H, where H represents a length of each of the first, second, and third sections of the second column. The method includes ejecting ink from the nozzles of the first, second, or third sections of the second column during each pass of the printhead over a printing medium as necessitated by characteristics of the color image, advancing the printing medium in the first direction by the length H, and ejecting ink from the nozzles of the first and third columns during every third pass that the printhead makes over the printing medium as necessitated by the characteristics of the color image.
It is another objective of the claimed invention to provide a method for compensating for a defective nozzle in the second column by printing ink with compensating nozzles in the first or third column.
The method for compensating for a defective nozzle includes detecting a defective nozzle in the first or second section of the second column, and ejecting ink from the nozzles of the first, second, or third sections the second column during each pass of the printhead over a printing medium as necessitated by characteristics of the color image. The method also includes compensating for the defective nozzle in the first or second section of the second column by ejecting ink two times from compensating nozzles in the first or third column, respectively, and advancing the printing medium in the first direction by the length H.
It is an advantage of the claimed invention that the printer contains both light colored and dark colored cyan and magenta ink for reducing the number of passes that the printhead must make over a printing medium. In addition, the printer can use light colored ink to compensate for defective nozzles that eject dark colored ink, thereby requiring no extra passes of the printhead over the printing medium for compensating a defective nozzle that ejects dark cyan or magenta ink.
These and other objectives of the claimed invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment, which is illustrated in the various figures and drawings.